LX7202-xx

Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 4

EMI Filter & ESD Protection for Up Stream USB

Ports

Copyright

© 2002

Rev. 1.0c, 2005-01-28

I N T E GRA T ED

PR ODUC T S

APPLICATION IN FORMATION (CONTINUED )

The USB v1.1 specification offers a 1.5 Mbps data

transfer rate known as Low-Speed which requires a 1.5 k Ω

pull-up resistor to be connected to the D- line. Slew rate

control is accomplished with 47pF attached to the

Voltage Supply (Vbus) is connected to Pin 1

Ground is connected to Pin 6

D+ from the connector is routed to Pin 2 and Pin 5 to

the D+ line of the USB Transceiver

D- from the connector is routed to Pin 3 (1.5 kΩ pull-

up resistor) and Pin 4 to the D- line of the USB Transceiver

cable

Peripheral

USB

Transceiver

GND

D+

D-

V

BUS

16

5

4

3

2

V

BUS

D

IN

D

IN

D

OUT

D

OUT

GND

LX7202

R

PU

Host

USB

Transceiver

GND

D+

D-

V

BUS

Figure 3 –

Connection for Low Speed Operation

ELECTROMAGNETIC EMISSION AND SUSCEPTABILITY

FCC Part 15 sets limits for maximum allowable EM

emission and susceptibility. There are two types of

emissions.

Conducted emissions with frequency of

emission of 0.45 to 30 MHz and Radiated emissions with

frequency of emission of 30 MHz to 40 GHz. All digital

computing devices including the peripheral devices must

comply. Examples of peripheral devices include terminals,

printers, external floppy disk drives and other fixed

adjustable data storage devices, video monitors, keyboards,

control cards, interface boards, external memory expansion

cards and other input/output devices that may or may not

contain digital circuitry. LX7202 is optimized to minimize

the radiated EMI which is the primary concern in devices

using USB. Refer to the typical filter response curve for

the attenuation characteristics of LX7202 over the

frequency range of 30KHz to 6GHz.